// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_QUIC_CRYPTO_CHANNEL_ID_H_
#define NET_QUIC_CRYPTO_CHANNEL_ID_H_

#include <memory>
#include <string>

#include "base/macros.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/quic/quic_types.h"

namespace net {

// ChannelIDKey is an interface that supports signing with and serializing a
// ChannelID key.
class NET_EXPORT_PRIVATE ChannelIDKey {
public:
    virtual ~ChannelIDKey() { }

    // Sign signs |signed_data| using the ChannelID private key and puts the
    // signature into |out_signature|. It returns true on success.
    virtual bool Sign(base::StringPiece signed_data,
        std::string* out_signature) const = 0;

    // SerializeKey returns the serialized ChannelID public key.
    virtual std::string SerializeKey() const = 0;
};

// ChannelIDSourceCallback provides a generic mechanism for a ChannelIDSource
// to call back after an asynchronous GetChannelIDKey operation.
class ChannelIDSourceCallback {
public:
    virtual ~ChannelIDSourceCallback() { }

    // Run is called on the original thread to mark the completion of an
    // asynchonous GetChannelIDKey operation. If |*channel_id_key| is not nullptr
    // then the channel ID lookup is successful. |Run| may take ownership of
    // |*channel_id_key| by calling |release| on it.
    virtual void Run(std::unique_ptr<ChannelIDKey>* channel_id_key) = 0;
};

// ChannelIDSource is an abstract interface by which a QUIC client can obtain
// a ChannelIDKey for a given hostname.
class NET_EXPORT_PRIVATE ChannelIDSource {
public:
    virtual ~ChannelIDSource() { }

    // GetChannelIDKey looks up the ChannelIDKey for |hostname|. On success it
    // returns QUIC_SUCCESS and stores the ChannelIDKey in |*channel_id_key|,
    // which the caller takes ownership of. On failure, it returns QUIC_FAILURE.
    //
    // This function may also return QUIC_PENDING, in which case the
    // ChannelIDSource will call back, on the original thread, via |callback|
    // when complete. In this case, the ChannelIDSource will take ownership of
    // |callback|.
    virtual QuicAsyncStatus GetChannelIDKey(
        const std::string& hostname,
        std::unique_ptr<ChannelIDKey>* channel_id_key,
        ChannelIDSourceCallback* callback)
        = 0;
};

// ChannelIDVerifier verifies ChannelID signatures.
class NET_EXPORT_PRIVATE ChannelIDVerifier {
public:
    // kContextStr is prepended to the data to be signed in order to ensure that
    // a ChannelID signature cannot be used in a different context. (The
    // terminating NUL byte is inclued.)
    static const char kContextStr[];
    // kClientToServerStr follows kContextStr to specify that the ChannelID is
    // being used in the client to server direction. (The terminating NUL byte is
    // included.)
    static const char kClientToServerStr[];

    // Verify returns true iff |signature| is a valid signature of |signed_data|
    // by |key|.
    static bool Verify(base::StringPiece key,
        base::StringPiece signed_data,
        base::StringPiece signature);

    // FOR TESTING ONLY: VerifyRaw returns true iff |signature| is a valid
    // signature of |signed_data| by |key|. |is_channel_id_signature| indicates
    // whether |signature| is a ChannelID signature (with kContextStr prepended
    // to the data to be signed).
    static bool VerifyRaw(base::StringPiece key,
        base::StringPiece signed_data,
        base::StringPiece signature,
        bool is_channel_id_signature);

private:
    DISALLOW_COPY_AND_ASSIGN(ChannelIDVerifier);
};

} // namespace net

#endif // NET_QUIC_CRYPTO_CHANNEL_ID_H_
